Dipole antenna having coaxial cable arms capacitively coupled to spaced tubular radiators



De@ 31, 1968 w. E. sT. vRAlN ET AL 3,419,872

DIPOLE ANTENNA HAVING COAXIAL CABLE ARMS CAPACITIVELY COUPLE'D TO SPACEDTUBULAR RADIATORS Filed June 2s, 196e United States Patent C) 3,419,872DIPOLE ANTENNA HAVING CDAXIAL CABLE ARMS CAPACITIVELY COUPLED T SPACEDTUBULAR RADIATORS Wallace E. St. Vrain, Kirkwood, and Joseph J. Mandino,Bridgeton, Mo., assignors to Mosley Electronics, Inc., Bridgeton, Mo., acorporation of Missouri Filed June 23, 1966, Ser. No. 559,817 3 Claims.(Cl. 343-792) This invention relates to a beam antenna of extremelysimple and inexpensive construction, incorporating means to improve theresistance of the antenna, permitting longer antenna elements bydecreasing the reactance of the elements. Specifically, the object ofthe Iinvention is to provide a beam antenna having one or more antennaelements with the usual coaxial cable connection for transmitting thepickup signal to a receiver, and with coaxial cable extensions throughthe hollow antenna element to decrease the reactance of the antenna,thereby permitting increased length of the antenna elements andresultant increased resistance. A general object of the invention,therefore, is to provide a beam antenna incorporated with extremelyinexpensive and simple means for decreasing the reactance of the antennaelement, to permit increasing the length of the elements to increase theresistance for improved reception.

Other objects and advantages will be apparent to those skilled in theart.

The drawing is a fragmentary view in longitudinal medial section througha typical single element antenna showing the connections for theimproved resistancereactance characteristics of the antenna,

While this invention is particularly described in connection with asingle element antenna, it will be appreciated by those skilled in theart that its features and advantages may be incorporated in anymulti-element antenna.

As shown in the drawing, the antenna i8 has a conventional elementsupport 9 mounted through any conventional aluminum 'clamping block 10by a U-bolt 11 to a conventional Iboorn 12. An electricallynon-conductive matching tube and connector 13 is hollow with open ends14 and 15 into which antenna or wall elements 16 and 17 are received.The wall elements 16 and 17 are mounted on insulators 18. Screws 19extend through the wall elements 16 and 17 and into the insulator 18 andother screws 20 from the underside of the element support 9 to fastenthe parts together as is clearly illustrated in the drawing.

An electrically conductive connector 22 having an externally threadedbase 23 is attached through -an opening 24 in the lower central wall ofthe matching tube and connector 13. The connector 22 has a passage'25through it in which an insulating grommet 26 is received. Anelectrically conductive terminal strip 27 is secured in the grommet 26.

A conventional coaxial cable 28 having a central hot wire 29 surroundedby an insulating sleeve, a meshed ground conductor 31, and an outerinsulating cover 32 is connected to the terminal strip 27 and the bodyof the connector 22. The hot wire 29 is tightly fastened to the terminalstrip 27, while the ground conductor 31 is tightly fastened and securedto the body of the connector 22. The other end of the coaxial cable 28is con- :nected to the receiver or transmitter (not shown).

According to this invention, another conventional cable 33 has itscentral wire 34 soldered to the upper end of the terminal strip 27 andextends through the wall 3,419,872 Patented Dec. 31, 1968 element 17,and a separate cable 35 has its central wire 36 soldered to theconnector 22 and extends through the other wall element 16.

The result of extending the coaxial cables 33 and 35 through the antennaelements 16 and 17, with the cable 33 connected directly to the hot wire29 of the cable 28 through the terminal strip 27 and the cable 35connected through the connector 2.2 to the ground conductor 31, is tode'crease the reactance of the antenna and permit greater resistance.This means that the antenna elements 16 and 17 (along with the usualextensions and trap assemblies) may be lengthened over what is standardfor antennas. Consequently, the gain of the antenna is greatly improvedand stronger signals are received by the receiver. For example, byextending the cables 33 and 35 through approximately three-fourths thelength of the respective antenna elements 16 and 17, the total lengthend to end between the left end of the antenna element 16 (and itsextensions and trap assembly) and the right end of the antenna element17 (and its extensions and trap assembly) can be 25 ft. 4 inches for theredector element, 25 ft. 2 inches for the radiator, and 20 ft. 8 inchesfor the director. Yet, this result is achieved with inexpensive partssimply constructed and installed.

Various changes and modifications may be made within the purview of thisinvention as will be readily -apparent to those skilled in the art. Suchchanges and modifications are within the scope and teaching of thisinvention as dened by the claims appended hereto.

What is claimed is:

1. An antenna assembly comprising a support, a central hollow tubehaving open ends, a first antenna element received within one open endof the hollow tube, a second antenna element received within the otheropen end of the hollow tube, both antenna elements being hollow andbeing supported with the hollow tube on the antenna support, a rstinsulated conductor extending through a substantial portion of thelength of the first antenna element, a second insulated conductorextending through a substantial portion of the length of the secondantenna element, forming a capacitor between conductor and element, acoaxial cable, the coaxial cable having the conventional hot line andground conductor separated by insulation, first means for connecting thefirst conductor to the hot wire of the coaxial cable, and second meansinsulated from the first means for connecting the second conductor tothe ground conductor of the coaxial cable.

2. The antenna assembly of claim 1 wherein the second means comprises anelectrically lconductive plug-like connector threaded through the wallof the hollow tube, the second conductor and the ground conductor of thecoaxial cable being soldered to the plug-like connector, and the firstmeans comprises an electrically conductive strip supported by aninsulator which in turn is supported by the plug-like connector, thefirst conductor and the hot wire of the coaxial cable being soldered tothe strip.

3. The antenna assembly of claim 1 wherein the first and secondconductors are coaxial cables.

References Cited UNITED STATES PATENTS ELI LIEBERMAN, Primary Examiner.

U.S. Cl. X.R. 343-802

1. AN ANTENNA ASSEMBLY COMPRISING A SUPPORT, A CENTRAL HOLLOW TUBEHAVING OPEN ENDS, A FIRST ANTENNA ELEMENT RECEIVED WITHIN ONE OPEN ENDOF THE HOLLOW TUBE, A SECOND ANTENNA ELEMENT RECEIVED WITHIN THE OTHEROPEN END OF THE HOLLOW TUBE, BOTH ANTENNA ELEMENTS BEING HOLLOW ANDBEING SUPPORTED WITH THE HOLLOW TUBE ON THE ANTENNA SUPPORT, A FIRSTINSULATED CONDUCTOR EXTENDING THROUGH A SUBSTANTIAL PORTION OF THELENGTH OF THE FIRST ANTENNA ELEMENT, A SECOND INSULATED CONDUCTOREXTENDING ING THROUGH A SUBSTANTIAL PORTION OF THE LENGTH OF THE SECONDANTENNA ELEMENT, FORMING A CAPACITOR BETWEEN CONDUCTOR AND ELEMENT, ACOAXIAL CABLE, THE COAXIAL CABLE HAVING THE CONVENTIONAL HOT LINE ANDGROUND CONDUCTOR SEPARATED BY INSULATION, FIRST MEANS FOR CONNECTING THEFIRST CONDUCTOR TO THE HOT WIRE OF THE COAXIAL CABLE, AND SECOND MEANSINSULATED FROM THE FIRST MEANS FOR CONNECTING THE SECOND CONDUCTOR TOTHE GROUND CONDUCTOR OF THE COAXIAL CABLE.